Microshoot Proliferation of Geranium Magniflorum ‘La Veta Lace'

Geranium magniflorum ‘La Veta Lace’ is an herbaceous perennial that grows within the USDA hardiness zones 4–8. La Veta Lace^® Geranium was originally collected from the Drakensburg Mountains of South Africa and it is a fern leaf species that has small purple blooms. Currently there is no published micropropagation protocol for G. magniflorum ‘La Veta Lace’. The objective of this study was to investigate the effects of nutrient salt formulations and different plant growth regulator concentrations on initiation and proliferation of microshoot culture of La Veta Lace^® Geranium. A 2 x 3 factorial combination of 1-naphthaleneacetic acid (NAA) concentrations (0.54 and 2.68 μM) and 6-benzylaminopurine (BA) concentrations (0.44, 2.22, and 4.44 μM) were compared to determine which plant growth regulator combination(s) would stimulate the proliferation of the most viable microshoots. Also, two nutrient salt formulations (MS, ½ MS) ranging from high to low salt formulations were studied to determine a suitable range of nutrient medium formulation for microshoot proliferation. Shoot tip explants that were 5 mm in length were used to initiate cultures and were maintained on the various factorial medium treatments plus 30 g/L sucrose and 7 g/L agar at a pH of 5.8.  Explants were incubated approximately 30 cm beneath cool-white fluorescent lamps that provide a photon flux of approximately 30 mmol·m^-2·s^-1 for a 16-h photoperiod at 25 ± 3°C. Nodal explants were transferred every 3 weeks for a total culture period of 6 weeks. At each transfer date, data were collected on microshoot number with a length greater than 2 mm. Developing microshoots were found to be adventitious, originating from callus produced from initial explants. Explants cultured on MS (high) nutrient salt formulation coupled with 0.54 μM NAA and 0.44 μM BA significantly produced the greatest number of microshoots per explant with an average of 12.3 shoots after 6 weeks of culturing.  Further research needs to be conducted on developing a suitable rooting medium along with acclimatization protocols.